Emergency stop system and emergency stop method

ABSTRACT

An emergency stop system includes a hazard switch that is a momentary switch, an automatic stop controller that performs automatic stop control for causing a vehicle to automatically stop when a predetermined condition is met, and a hazard light controller that controls hazard lights. While automatic stop control is not being performed, the hazard light controller switches the hazard lights between a flashing state and a turned-off state each time a user presses the hazard switch. The hazard light controller brings the hazard lights into the flashing state upon start of the automatic stop control, and turns off the hazard lights (i.e., transitions the hazard lights to the turned-off state) upon depression of the hazard switch while the hazard lights are flashing during execution of the automatic stop control.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 toJapanese Patent Application No. 2015-212389, filed Oct. 28, 2015,entitled “Emergency Stop System and Emergency Stop Method.” The contentsof this application are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present disclosure relates to an emergency stop system and anemergency stop method for bringing a vehicle to an emergency stop.

BACKGROUND

Emergency stop systems are known in the related art for dealing with asituation where it is difficult for a driver of a vehicle to continue todrive the vehicle.

For example, there has been proposed an emergency warning apparatus fora vehicle, which is provided with an emergency warning device for, inresponse to depression of an emergency warning button, sending a requestto a control device for the vehicle to bring the vehicle to an automaticstop and sending instructions to a hazard light control device to turnon hazard lights (see Japanese Unexamined Patent Application PublicationNo. 2003-233886).

The proposed emergency warning apparatus for a vehicle allows the hazardlights to be turned on when performing a process for bringing thevehicle to an automatic stop, which can alert nearby vehicles such asvehicles approaching from the rear that the vehicle is operating underemergency stop conditions.

In the technique disclosed in Japanese Unexamined Patent ApplicationPublication No. 2003-233886, a user operation potentially conflicts withan operation of controlling the hazard lights to be turned on, which isinvolved in a process for bringing the vehicle to an automatic stop.Thus, the hazard lights may be unintentionally controlled to be turnedon and such control may cause the user to feel awkward.

SUMMARY

The present application describes, for example, an emergency stop systemand an emergency stop method which may eliminate or reduce the awkwardfeeling that the user experiences during the turning on of hazardlights, which is involved in a process for bringing a vehicle to anautomatic stop.

An emergency stop system according to an aspect of the presentdisclosure includes a hazard switch, an automatic stop controller, and ahazard light controller. The hazard switch is a momentary switch adaptedto provide an instruction to flash or turn off hazard lights of avehicle. The automatic stop controller performs automatic stop controlfor causing the vehicle to automatically stop when a predeterminedcondition is met. The hazard light controller controls the hazard lightsso as to switch the hazard lights between a flashing state and aturned-off state each time a user presses the hazard switch while theautomatic stop control is not being performed, to bring the hazardlights into the flashing state upon start of the automatic stop control,and to turn off the hazard lights upon depression of the hazard switchwhile the hazard lights are flashing during execution of the automaticstop control.

Prior to the description of the operation and advantages of theemergency stop system according to the aspect of the present disclosure,a brief description is given of a traditional hazard switch.

The traditional hazard switch is typically an alternate switch. When thealternate switch is pressed while in a free state (e.g., in its releasedposition), the alternate switch transitions to an operating state (e.g.,its depressed position) and is held in the operating state until thealternate switch is pressed again. When the alternate switch is pressedwhile in the operating state, the alternate switch transitions to thefree state and is held in the free state until the alternate switch ispressed again.

The traditional hazard switch is configured such that the hazard lightsare controlled to be turned off while the alternate switch is in thefree state and the hazard lights are controlled to flash while thealternate switch is in the operating state.

However, once automatic stop control is started, the hazard lights arecaused to flash regardless of the operation of the hazard switch. Thus,in a case where an alternate switch is adopted, the hazard lights arebrought into a flashing state even while the alternate switch is in afree state (or in its released position), which may make the user (i.e.,the vehicle driver or a passenger) feel awkward.

In addition, in order to turn off the hazard lights which are broughtinto the flashing state due to automatic stop control, the user pressesthe alternate switch once to bring the alternate switch into anoperating state (or its depressed position) and then presses thealternate switch again to bring the alternate switch into a free state(or its released position). This operation may inconvenience the user.

To address the issues described above, in the emergency stop systemaccording to the aspect of the present disclosure, while automatic stopcontrol is not being performed, the hazard light controller allows thehazard lights to be switched between a flashing state and a turned-offstate each time the hazard switch is pressed.

Here, in the aspect of the present disclosure, the hazard switch isimplemented as a momentary switch. The momentary switch is configuredto, when the momentary switch is pressed while in a free state (e.g., inits released position), temporarily transition to an operating state(e.g., its depressed position) and then return to the free state. Thisconfiguration allows the hazard switch to be held in the free state whenthe hazard switch is not being operated by the user, regardless ofwhether the hazard lights are in a flashing state or a turned-off state.

In addition, when the hazard lights are controlled to flash by thehazard light controller in response to the execution of automatic stopcontrol by the automatic stop controller, similarly to when the hazardlights are in a flashing state while automatic stop control is not beingperformed, the hazard switch is in the free state.

In addition, when the user presses the hazard switch once while thehazard lights are in a flashing state due to automatic stop control, thehazard lights are turned off by the hazard light controller. Also inthis case, similarly to when the hazard lights are in a turned-off statewhile automatic stop control is not being performed, the hazard switchis in the free state.

As described above, the emergency stop system according to the aspect ofthe present disclosure may eliminate or reduce the awkward feeling thatthe user experiences for the state of the hazard switch and eliminate orreduce the inconvenience caused by the operation of turning off thehazard lights using the hazard switch during the flashing of the hazardlights which is involved in a process for bringing the vehicle to anautomatic stop.

Preferably, the emergency stop system further includes an emergency stopswitch separate from the hazard switch, and the predetermined conditionincludes a condition in which the emergency stop switch is pressed.

In the emergency stop system having the configuration described above,the automatic stop controller performs automatic stop control oncondition that the emergency stop switch is operated.

The user may wish to turn off the hazard lights in some cases, such aswhen the emergency stop switch has been pressed unintentionally due toan operation error or the like but the user does not recognize thedepression of the emergency stop switch or when the user wishes totemporarily continue to drive the vehicle although the user hasintentionally pressed the emergency stop switch. In such cases, asdescribed above, the user may be able to turn off the hazard lights byoperating the hazard switch once.

Preferably, the emergency stop system further includes a drivingoperation detector that detects a presence or absence of a predetermineddriving operation of the vehicle, and the predetermined conditionincludes a condition in which the absence of the predetermined drivingoperation is continuously detected by the driving operation detector fora predetermined first period.

In the emergency stop system having the configuration described above,the automatic stop controller performs automatic stop control oncondition that the absence of the predetermined driving operation iscontinuously detected by the driving operation detector for apredetermined first period.

In some cases, such as when the user (the vehicle driver) wishes toresume the driving operation, the user may wish to turn off the hazardlights by using the hazard switch even during execution of the automaticstop control. In such cases, the user may be able to turn off the hazardlights by pressing the hazard switch once.

Preferably, the emergency stop system further includes a drivingoperation detector that detects a presence or absence of a predetermineddriving operation of the vehicle, and the automatic stop controllerterminates the automatic stop control in a case where the presence ofthe predetermined driving operation is continuously detected by thedriving operation detector for a predetermined second period duringexecution of the automatic stop control.

In the emergency stop system having the configuration described above,if the presence of the predetermined driving operation is continuouslydetected by the driving operation detector for a predetermined secondperiod during execution of the automatic stop control, the automaticstop control is terminated. If the driving operation detected by thedriving operation detector continues for a predetermined second periodduring execution of the automatic stop control, the vehicle driver ismore likely to have a driving intention. Thus, by terminating theautomatic stop control, it may be possible to achieve the controlintended by the vehicle driver.

In some cases, the user attempts to turn off the hazard lights by usingthe hazard switch before or after the resumption of the drivingoperation. In such cases, the user may be able to turn off the hazardlights by pressing the hazard switch once.

In the emergency stop system, preferably, the hazard light controllercauses the hazard lights to be turned off upon completion of theautomatic stop control in a case where the hazard lights are broughtinto the flashing state in accordance with the automatic stop control,and continues the flashing state of the hazard lights after completionof the automatic stop control in a case where the hazard lights arebrought into the flashing state in response to depression of the hazardswitch before start of the automatic stop control or during execution ofthe automatic stop control.

While the hazard lights are flashing in accordance with automatic stopcontrol, if the automatic stop control is completed, in many case, it ispredicted that the flashing of the hazard lights will no longer benecessary. Thus, even if the hazard light controller terminates theflashing of the hazard lights in response to the completion of theautomatic stop control, the user will not feel very awkward.

In contrast, if the user presses the hazard switch to bring the hazardlights into the flashing state, it is predicted that the user will wishto flash the hazard lights regardless of the execution of automatic stopcontrol. In this case, the hazard light controller causes the hazardlights to continue to flash even after the automatic stop control hasbeen completed, thereby reducing or preventing the awkward feeling thatthe user experiences.

In the emergency stop system, preferably, the hazard light controller isconfigured to turn off the hazard lights when the automatic stopcontroller starts execution of predetermined control during execution ofthe automatic stop control, and to cause the hazard lights to resumeflashing upon completion of the predetermined control during executionof the automatic stop control.

Keeping the hazard lights flashing during execution of the automaticstop control may make the user and occupants of other vehicles feelawkward. The emergency stop system having the configuration describedabove may allows the hazard light controller to control the flashing orturning off of the hazard lights, thereby eliminating or reducing theawkward feeling that user or occupants of other vehicles experience forthe flashing or turning off of the hazard lights.

In the emergency stop system having the configuration described above,preferably, the predetermined control comprises a lane change thatinvolves causing turn signal lights of the vehicle to flash.

When a lane change which involves causing turn signal lights to flash isperformed, the flashing of the turn signal lights may be visuallyindistinguishable while the hazard lights are in the flashing state. Toaddress this situation, in the emergency stop system having theconfiguration described above, the hazard light controller turns off thehazard lights when a lane change is performed during execution of theautomatic stop control. This may eliminate or reduce the awkward feelingthat occupants of other vehicles experience because the flashing of theturn signal lights are visually indistinguishable.

Preferably, the emergency stop system further includes an accelerationoperation detector that detects an acceleration operation of thevehicle. Preferably, furthermore, the automatic stop controller isconfigured to interrupt the automatic stop control in a case where theacceleration operation is detected by the acceleration operationdetector during execution of the automatic stop control, and isconfigured to terminate the automatic stop control in a case where theacceleration operation is continuously detected by the accelerationoperation detector for a predetermined third period or longer afterinterruption of the automatic stop control, and to resume the automaticstop control in a case where the acceleration operation is no longerdetected by the acceleration operation detector before the third periodelapses after interruption of the automatic stop control. Preferably,moreover, the hazard light controller is configured to turn off thehazard lights during interruption of the automatic stop control, and tocause the hazard lights to resume flashing in response to resumption ofthe automatic stop control.

In the emergency stop system having the configuration described above,in response to an acceleration operation being detected by theacceleration operation detector during execution of the automatic stopcontrol, the automatic stop controller interrupts the automatic stopcontrol and the hazard light controller turns off the hazard lights.This allows the user and occupants of other vehicles to recognizeinterruption of the automatic stop control without user inconveniencecaused by operation of the hazard switch.

In addition, if the acceleration operation continues for a predeterminedperiod (third period) or longer, it is predicted that the accelerationoperation is an operation based on the driving intention of the vehicledriver, whereas, if the duration of the acceleration operation is lessthan the predetermined period (third period), it is difficult todetermine whether or not the acceleration operation is based on thedriving intention of the driver. To address this situation, theautomatic stop controller performs control to terminate the automaticstop control or to resume the automatic stop control in accordance withwhether or not the acceleration operation continues for thepredetermined third period or longer. Thus, the control intended by thevehicle driver is achievable.

Furthermore, the hazard light controller causes the hazard lights toresume flashing in response to the resumption of the automatic stopcontrol. This allows the user and occupants of other nearby vehicles torecognize the resumption of the automatic stop control without userinconvenience caused by operation of the hazard switch.

As described above, the emergency stop system having the configurationdescribed above allows the driving intention of the user to be reflectedand allows the hazard lights to be controlled to flash or stop flashingin accordance with the state of the execution of automatic stop control.This allows the user and occupants of other vehicles to recognize thestate of the execution of automatic stop control without userinconvenience caused by operation of the hazard switch.

In the emergency stop system having the configuration described above,preferably, the hazard light controller brings the hazard lights intothe flashing state upon depression of the hazard switch while the hazardlights are turned off by interruption of the automatic stop control.

When the hazard switch is pressed even if the hazard lights have beenturned off in association with automatic stop control, it is predictedthat the user will have an intention to resume flashing the hazardlights. To address this situation, in the emergency stop system havingthe configuration described above, the hazard light controller bringsthe hazard lights into the flashing state.

An emergency stop system according to another aspect of the presentdisclosure includes an automatic stop controller, an accelerationoperation detector, and a hazard light controller. The automatic stopcontroller performs automatic stop control to cause a vehicle toautomatically stop when a predetermined condition is met. Theacceleration operation detector detects an acceleration operation of thevehicle. The hazard light controller brings hazard lights of the vehicleinto a flashing state upon start of the automatic stop control. Theautomatic stop controller is configured to interrupt the automatic stopcontrol in a case where the acceleration operation is detected by theacceleration operation detector during execution of the automatic stopcontrol, and is configured to terminate the automatic stop control in acase where the acceleration operation is continuously detected by theacceleration operation detector for a predetermined fourth period orlonger after interruption of the automatic stop control, and to resumethe automatic stop control in a case where a duration over which theacceleration operation is detected by the acceleration operationdetector after interruption of the automatic stop control is less thanthe fourth period. The hazard light controller is configured to turn offthe hazard lights in response to interruption of the automatic stopcontrol, and to cause the hazard lights to flash in response toresumption of the automatic stop control.

In the emergency stop system having the configuration described above,in response to an acceleration operation being detected by theacceleration operation detector during execution of the automatic stopcontrol, the automatic stop controller interrupts the automatic stopcontrol and the hazard light controller turns off the hazard lights.This allows the user and occupants of other vehicles to recognizeinterruption of the automatic stop control.

In addition, if the acceleration operation continues for a predeterminedperiod (fourth period) or longer, it is predicted that the accelerationoperation is an operation based on the driving intention of the vehicledriver, whereas, if the duration of the acceleration operation is lessthan the predetermined period (fourth period), it is difficult todetermine whether or not the acceleration operation is based on thedriving intention of the driver. To address this situation, theautomatic stop controller performs control to terminate the automaticstop control or to resume the automatic stop control in accordance withwhether or not the acceleration operation continues for thepredetermined fourth period or longer. Thus, the control intended by thevehicle driver is achievable.

Furthermore, the hazard light controller causes the hazard lights toresume flashing in response to the resumption of the automatic stopcontrol. This allows the user and occupants of other nearby vehicles torecognize the resumption of the automatic stop control.

As described above, the emergency stop system having the configurationdescribed above allows the driving intention of the user to be reflectedand allows the hazard lights to be controlled to flash or stop flashingin accordance with the state of the execution of automatic stop control.This allows the user and occupants of other vehicles to recognize thestate of the execution of automatic stop control.

An emergency stop method according to still another aspect of thepresent disclosure is an emergency stop method performed by a systemincluding a hazard switch and an automatic stop controller, the hazardswitch being a momentary switch adapted to provide an instruction toflash or turn off hazard lights of a vehicle, the automatic stopcontroller performing automatic stop control for causing the vehicle toautomatically stop when a predetermined condition is met. The emergencystop method includes the steps of switching the hazard lights between aflashing state and a turned-off state each time a user presses thehazard switch while the automatic stop control is not being performed;bringing the hazard lights into the flashing state upon start of theautomatic stop control; and turning off the hazard lights upondepression of the hazard switch while the hazard lights are flashingduring execution of the automatic stop control.

By implementing the emergency stop method according to the aspect of thepresent disclosure while applying the emergency stop method to a system,it may be possible to achieve an operation and advantages similar tothose of the emergency stop system according to the aspects of thepresent disclosure described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the disclosure will become apparent in the followingdescription taken in conjunction with the following drawings.

FIG. 1 is an overall configuration diagram of an emergency stop systemof one embodiment.

FIG. 2 is a state transition diagram of a hazard light controller of oneembodiment.

FIGS. 3A to 3C are time charts illustrating an example relationshipbetween the input and output of the hazard light controller, in whichFIG. 3A is a time chart illustrating a hazard control request, FIG. 3Bis a time chart illustrating a hazard-switch pressing signal, and FIG.3C is a time chart illustrating a flashing control signal.

FIGS. 4A to 4C are time charts illustrating another example relationshipbetween the input and output of the hazard light controller, in whichFIG. 4A is a time chart illustrating a hazard control request, FIG. 4Bis a time chart illustrating a hazard-switch pressing signal, and FIG.4C is a time chart illustrating a flashing control signal.

FIGS. 5A and 5B are diagrams illustrating the activation of theemergency stop system in automatic stop control, in which FIG. 5A is adiagram illustrating the activation of each component and FIG. 5B is adiagram illustrating a vehicle position and the flashing state of thelights.

FIGS. 6A and 6B are diagrams illustrating the activation of theemergency stop system in response to depression of a hazard switchbefore execution of automatic stop control, in which FIG. 6A is adiagram illustrating the activation of each component and FIG. 6B is adiagram illustrating a vehicle position and the flashing state of thelights.

FIGS. 7A and 7B are diagrams illustrating the activation of theemergency stop system when a lane change is performed in automatic stopcontrol, in which FIG. 7A is a diagram illustrating the activation ofeach component and FIG. 7B is a diagram illustrating a vehicle positionand the flashing state of the lights.

FIGS. 8A and 8B are diagrams illustrating the activation of theemergency stop system in response to depression of the hazard switchwhen a lane change is performed due to automatic stop control, in whichFIG. 8A is a diagram illustrating the activation of each component andFIG. 8B is a diagram illustrating a vehicle position and the flashingstate of the lights.

FIGS. 9A and 9B are diagrams illustrating the activation of theemergency stop system upon detection of continuous accelerator operationin automatic stop control, in which FIG. 9A is a diagram illustratingthe activation of each component and FIG. 9B is a diagram illustrating avehicle position and the flashing state of the lights.

FIGS. 10A and 10B are diagrams illustrating the activation of theemergency stop system upon detection of continuous accelerator operationand detection of depression of the hazard switch in automatic stopcontrol, in which FIG. 10A is a diagram illustrating the activation ofeach component and FIG. 10B is a diagram illustrating a vehicle positionand the flashing state of the lights.

FIGS. 11A and 11B are diagrams illustrating the activation of theemergency stop system upon detection of temporary accelerator operationin automatic stop control, in which FIG. 11A is a diagram illustratingthe activation of each component and FIG. 11B is a diagram illustratinga vehicle position and the flashing state of the lights.

FIGS. 12A and 12B are diagrams illustrating the activation of theemergency stop system upon detection of temporary accelerator operationand detection of depression of the hazard switch in automatic stopcontrol, in which FIG. 12A is a diagram illustrating the activation ofeach component and FIG. 12B is a diagram illustrating a vehicle positionand the flashing state of the lights.

DETAILED DESCRIPTION

Configuration of Emergency Stop System

Referring to FIG. 1, an emergency stop system 1, which is mounted in avehicle, includes an emergency stop switch 111, an emergency warningsystem 112, a front camera 121, an automatic stop controller 122, anoperation detector 123, a stability control unit 131, a steering controlunit 132, an information providing control unit 141, a meter 151, ahazard light controller 161, and a hazard switch 171. The operationdetector 123 constitutes a “driving operation detector” and an“acceleration operation detector” disclosed herein. The hazard lightcontroller 161 constitutes a “hazard light controller” disclosed herein.

The emergency stop switch 111 is connected to the emergency warningsystem 112 and the automatic stop controller 122 via hard wires. Theemergency stop switch 111 is configured to output anemergency-stop-switch pressing signal to the emergency warning system112 and the automatic stop controller 122 when depression of theemergency stop switch 111 by a vehicle occupant (the driver or apassenger) is detected.

The emergency warning system 112 is connected to the emergency stopswitch 111 via a hard wire.

The emergency warning system 112 is configured to place a call to anexternal emergency call center via a telephone communication networkwhen an emergency-stop-switch pressing signal is input from theemergency stop switch 111, so as to allow the vehicle occupant to have atelephone conversation with the contact person at the external emergencycall center.

The front camera 121 is connected to the automatic stop controller 122via a communication cable. The front camera 121 is configured to outputto the automatic stop controller 122 a captured image of an area in thedirection of travel of the vehicle.

The automatic stop controller 122 is connected to the emergency stopswitch 111 via a hard wire, and is connected to the front camera 121,the operation detector 123, the stability control unit 131, the steeringcontrol unit 132, the information providing control unit 141, and themeter 151 via communication cables. The automatic stop controller 122includes a radar device (not illustrated) that monitors the presence ofobjects in the direction of travel of the vehicle.

The automatic stop controller 122 is implemented as an electroniccontrol unit (ECU) or the like. The automatic stop controller 122 isconfigured to output a combination of a braking control request and adeceleration, a combination of a steering request and a steering requestvalue, status information, and a hazard control request to the stabilitycontrol unit 131, the steering control unit 132, the informationproviding control unit 141, and the meter 151, respectively, on thebasis of an emergency-stop-switch pressing signal from the emergencystop switch 111, a captured image from the front camera 121, operationinformation from the operation detector 123, and information input fromthe radar device which indicates whether or not there is an object aheadof the vehicle. The ECU may include CPU which executes programs storedin a memory device to implement functions described in the embodimentsof the present application. Those functions may be implemented byhardware such as a circuitry(s).

The hazard control request is a request that is output at all times andthat takes four values of 0 to 3. When making a request to keep thehazard lights in a flashing state or a turned-off state, the automaticstop controller 122 outputs a hazard control request with the value “0”to the meter 151.

For example, when making a request to start flashing the hazard lightsin association with the start of the execution of automatic stop control(deceleration control and steering control to make a stop) or inassociation with the completion of the execution of a lane change, theautomatic stop controller 122 outputs a hazard control request with thevalue “1” (for flashing) to the meter 151.

For example, when making a request to start turning off the hazardlights in association with the completion of the execution of theautomatic stop control, the automatic stop controller 122 outputs ahazard control request with the value “2” (for turn-off) to the meter151.

For example, when making a request to temporarily stop the flashing ofthe hazard lights in association with the start of the execution of alane change or in association with the interruption of the automaticstop control, the automatic stop controller 122 outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to the meter151.

The operation detector 123 is connected to the automatic stop controller122 via a communication cable. The operation detector 123 is implementedas an accelerator position sensor or the like, and is configured tooutput operation information indicating the presence of individualoperations, including accelerator opening degree information, to theautomatic stop controller 122.

The stability control unit 131 is connected to the automatic stopcontroller 122 via a communication cable, and is connected to a stoplight 133 mounted on the vehicle via a hard wire. The stability controlunit 131 is configured to execute braking control of the vehicle orvehicle speed maintenance control of the vehicle on the basis of thebraking control request and the deceleration input from the automaticstop controller 122. The stability control unit 131 is also configuredto output a stop-light turn on request to execute control to turn on oroff the stop light 133.

The steering control unit 132 is connected to the automatic stopcontroller 122 via a communication cable. The steering control unit 132is configured to execute steering control of the vehicle on the basis ofthe steering request and the steering request value input from theautomatic stop controller 122.

The information providing control unit 141 is connected to the automaticstop controller 122 via a communication cable, and is connected to aspeaker 142 and a display 143, which are mounted in the vehicle, viawired cables such as analog cables. The information providing controlunit 141 is configured to output a vehicle control state and a hazardlight control state to the speaker 142 and the display 143 on the basisof status information input from the automatic stop controller 122.Examples of the vehicle control state include a state in which theautomatic stop control has started, a state in which the automatic stopcontrol is in progress, a state in which a lane change is in progress,and a state in which the automatic stop control has been completed.Examples of the hazard light control state include a state in whichautomatic flashing of the hazard lights has started, automatic flashingof the hazard lights has been temporarily stopped, and automaticflashing of the hazard lights has been completed.

The meter 151 is connected to the automatic stop controller 122 and thehazard light controller 161 via communication cables. The meter 151provides a visual indication of the flashing state of the hazard lightsin accordance with a hazard control request input from the automaticstop controller 122, and outputs to the hazard light controller 161 ahazard control request having a value identical to that of the inputhazard control request.

The hazard light controller 161 is connected to the hazard switch 171via a hard wire or the like, and is also connected to a left front light163L, a right front light 163R, a left rear light 164L, and a right rearlight 164R, which are respectively located on the left side at thefront, the right side at the front, the left side at the rear, and theright side at the rear of the vehicle.

Each of the left front light 163L, the right front light 163R, the leftrear light 164L, and the right rear light 164R is configured to alsofunction as a turn signal light (or a direction indicator).

The hazard light controller 161 is implemented as an ECU or the like,and is configured to output a request for flashing each of the leftfront light 163L, the right front light 163R, the left rear light 164L,and the right rear light 164R or output a request for turning off eachof the left front light 163L, the right front light 163R, the left rearlight 164L, and the right rear light 164R (“flashing control request”)in accordance with a hazard control request input from the meter 151 anda hazard-switch pressing signal input from the hazard switch 171. TheECU may include CPU which executes programs stored in a memory device toimplement functions described in the embodiments of the presentapplication. Those functions may be implemented by hardware such as acircuitry(s).

The hazard light controller 161 outputs a flashing control request withthe value “0” to each of the lights 163L, 163R, 164L, and 164R to turnoff each of the lights 163L, 163R, 164L, and 164R. The hazard lightcontroller 161 outputs a flashing control request with the value “1” toeach of the lights 163L, 163R, 164L, and 164R to flash each of thelights 163L, 163R, 164L, and 164R.

Further, the hazard light controller 161 stores, as an internalvariable, a binary manual flashing state variable of 0 or 1 indicating aflashing state corresponding to an operation performed on the hazardswitch 171.

The hazard switch 171 is connected to the hazard light controller 161via a hard wire or the like. The hazard switch 171 is implemented as amomentary switch, and is configured to output a hazard-switch pressingsignal to the hazard light controller 161 upon detection of depressionof the hazard switch 171.

The hazard switch 171 outputs the value “0” to the hazard lightcontroller 161 when no depression of the hazard switch 171 is detected,and outputs the value “1” to the hazard light controller 161 whendepression of the hazard switch 171 is detected.

States of Hazard Light Controller

Next, state transitions of the hazard light controller 161 will bedescribed with reference to FIG. 2.

As illustrated in FIG. 2, the hazard light controller 161 is configuredto transition to any one of first to sixth states S1 to S6 in responseto the input of a hazard-switch pressing signal and a hazard controlrequest.

When the emergency stop system 1 is activated in association with theoperation of an ignition switch of the vehicle, the hazard lightcontroller 161 transitions to the first state S1.

The first state S1 is a state in which the lights 163L, 163R, 164L, and164R are kept in a turned-off state while automatic stop control is notbeing performed. In the first state S1, the hazard light controller 161outputs a flashing control request with the value “0” to perform controlto turn off each of the lights 163L, 163R, 164L, and 164R. The hazardlight controller 161 further sets the manual flashing state variable to0.

In the first state S1, as indicated by an arrow C12, when ahazard-switch pressing signal with the value “1” is input (in otherwords, when the hazard switch 171 is pressed), the hazard lightcontroller 161 transitions to the second state S2.

In the first state S1, as indicated by an arrow C14, when a hazardcontrol request with the value “1” (for flashing) is input (in otherwords, when a request is made by the automatic stop controller 122 tostart flashing the lights), the hazard light controller 161 transitionsto the fourth state S4.

The second state S2 is a state in which the lights 163L, 163R, 164L, and164R are kept in a flashing state while automatic stop control is notbeing performed. In the second state S2, the hazard light controller 161outputs a flashing control request with the value “1” to perform controlto flash each of the lights 163L, 163R, 164L, and 164R. The hazard lightcontroller 161 further sets the manual flashing state variable to 1.

In the second state S2, as indicated by an arrow C21, when ahazard-switch pressing signal with the value “1” is input, the hazardlight controller 161 transitions to the first state S1.

In the second state S2, as indicated by an arrow C24, when a hazardcontrol request with the value “1” (for flashing) is input, the hazardlight controller 161 transitions to the fourth state S4.

The third state S3 is a state in which the lights 163L, 163R, 164L, and164R are kept in a turned-off state when an action such as a lane changeis performed while automatic stop control is being performed. In thethird state S3, the hazard light controller 161 outputs a flashingcontrol request with the value “0” to perform control to turn off eachof the lights 163L, 163R, 164L, and 164R.

In the third state S3, as indicated by an arrow C31, when a hazardcontrol request with the value “2” (for turn-off) is input and themanual flashing state variable is 0, the hazard light controller 161transitions to the first state S1.

In the third state S3, as indicated by an arrow C32, when a hazardcontrol request with the value “2” (for turn-off) is input and themanual flashing state variable is 1, the hazard light controller 161transitions to the second state S2.

In the third state S3, as indicated by an arrow C34, when a hazardcontrol request with the value “1” (for flashing) is input, the hazardlight controller 161 transitions to the fourth state S4. This transitionis made when, for example, a lane change has been completed in automaticstop control.

In the third state S3, as indicated by an arrow C36, when ahazard-switch pressing signal with the value “1” is input (in otherwords, when the hazard switch 171 is pressed), the hazard lightcontroller 161 transitions to the sixth state S6.

The fourth state S4 is a state in which the lights 163L, 163R, 164L, and164R are kept in a flashing state when operation such as decelerationcontrol is performed while automatic stop control is being performed. Inthe fourth state S4, the hazard light controller 161 outputs a flashingcontrol request with the value “1” to perform control to flash each ofthe lights 163L, 163R, 164L, and 164R.

In the fourth state S4, as indicated by an arrow C41, when a hazardcontrol request with the value “2” (for turn-off) is input and themanual flashing state variable is 0, the hazard light controller 161transitions to the first state S1.

In the fourth state S4, as indicated by an arrow C42, when a hazardcontrol request with the value “2” (for turn-off) is input and themanual flashing state variable is 1, the hazard light controller 161transitions to the second state S2.

In the fourth state S4, as indicated by an arrow C43, when a hazardcontrol request with the value “3” (for temporary stop of flashing) isinput, the hazard light controller 161 transitions to the third stateS3. This transition is made when, for example, a lane change is startedin the automatic stop control.

In the fourth state S4, as indicated by an arrow C45, when ahazard-switch pressing signal with the value “1” is input (in otherwords, when the hazard switch 171 is pressed), the hazard lightcontroller 161 transitions to the fifth state S5.

The fifth state S5 is a state in which the lights 163L, 163R, 164L, and164R are kept in a turned-off state in response to a hazard-switchpressing signal while automatic stop control is being performed. In thefifth state S5, the hazard light controller 161 outputs a flashingcontrol request with the value “0” to perform control to turn off eachof the lights 163L, 163R, 164L, and 164R.

In the fifth state S5, as indicated by an arrow C51, when a hazardcontrol request with the value “2” (for turn-off) is input, the hazardlight controller 161 transitions to the first state S1.

In the fifth state S5, as indicated by an arrow C56, when ahazard-switch pressing signal with the value “1” is input (in otherwords, when the hazard switch 171 is pressed), the hazard lightcontroller 161 transitions to the sixth state S6.

The sixth state S6 is a state in which the lights 163L, 163R, 164L, and164R are kept in a flashing state in response to a hazard-switchpressing signal while automatic stop control is being performed. In thesixth state S6, the hazard light controller 161 outputs a flashingcontrol request with the value “1” to perform control to flash each ofthe lights 163L, 163R, 164L, and 164R.

In the sixth state S6, as indicated by an arrow C62, when a hazardcontrol request with the value “2” (for turn-off) is input, the hazardlight controller 161 transitions to the second state S2.

In the sixth state S6, as indicated by an arrow C65, when ahazard-switch pressing signal with the value “1” is input (in otherwords, when the hazard switch 171 is pressed), the hazard lightcontroller 161 transitions to the fifth state S5.

Relationships Between Inputs for Hazard Light Controller and RequestOutput from Hazard Light Controller

Next, relationships between inputs (a hazard control request and ahazard-switch pressing signal) for the hazard light controller 161 and aflashing control request output from the hazard light controller 161will be described with reference to FIGS. 3A to 3C and FIGS. 4A to 4C.

FIG. 3A and FIG. 4A are graphs with the vertical axis representing thevalue of the hazard control request and the horizontal axis being thetime axis. FIG. 3B and FIG. 4B are graphs with the vertical axisrepresenting the value of the hazard-switch pressing signal and thehorizontal axis being the time axis. FIG. 3C and FIG. 4C are graphs withthe vertical axis representing the value of the flashing control requestand the horizontal axis being the time axis. The graphs illustrated inFIG. 3C and FIG. 4C also depict the state of the respective lights,which is either a flashing state or a turned-off state, at each point intime, and the state of the hazard light controller 161 is represented bya number in parentheses. In the following, the flashing control requestis also referred to as “flashing control signal”.

At time t0, the hazard light controller 161 is in the first state S1. Inthe first state S1, the hazard light controller 161 receives input of ahazard control request with the value “0” and a hazard-switch pressingsignal with the value “0”, and the hazard light controller 161 outputs aflashing control signal with the value “0”. In the first state S1, thelights 163L, 163R, 164L, and 164R are each controlled to be turned off.The manual flashing state variable is set to 0.

At time t1, when a hazard-switch pressing signal with the value “1” isinput from the hazard switch 171 (in other words, when depression of thehazard switch 171 is detected), the hazard light controller 161transitions from the first state S1 to the second state S2 (the arrowC12 in FIG. 2) and outputs a flashing control signal with the value “1”.In the second state S2, the lights 163L, 163R, 164L, and 164R are eachcontrolled to flash. The hazard light controller 161 further sets themanual flashing state variable to 1.

At time t2, when a hazard-switch pressing signal with the value “1” isinput again from the hazard switch 171 (in other words, when depressionof the hazard switch 171 is detected again), the hazard light controller161 transitions from the second state S2 to the first state S1 (thearrow C21 in FIG. 2) and outputs a flashing control signal with thevalue “0”. In the first state S1, the lights 163L, 163R, 164L, and 164Rare each controlled to be turned-off. The hazard light controller 161further sets the manual flashing state variable to 0.

At time t3, when a hazard control request with the value “1” (forflashing) is input in association with, for example, the start ofautomatic stop control by the automatic stop controller 122, the hazardlight controller 161 transitions from the first state S1 to the fourthstate S4 (the arrow C14 in FIG. 2) and outputs a flashing control signalwith the value “1”. In the fourth state S4, the lights 163L, 163R, 164L,and 164R are each controlled to flash.

At time t4, when a hazard control request with the value “3” (fortemporary stop of flashing) is input in association with, for example,the start of a lane change during execution of the automatic stopcontrol by the automatic stop controller 122, the hazard lightcontroller 161 transitions from the fourth state S4 to the third stateS3 (the arrow C43 in FIG. 2) and outputs a flashing control signal withthe value “0”. In the third state S3, the lights 163L, 163R, 164L, and164R are each controlled to be turned off.

At time t5, when a hazard control request with the value “1” (forflashing) is input in association with, for example, the completion ofthe lane change during execution of the automatic stop control by theautomatic stop controller 122, the hazard light controller 161transitions from the third state S3 to the fourth state S4 (the arrowC34 in FIG. 2) and outputs a flashing control signal with the value “1”.In the fourth state S4, the lights 163L, 163R, 164L, and 164R are eachcontrolled to flash.

At time t6, when a hazard-switch pressing signal with the value “1” isinput from the hazard switch 171 (in other words, when depression of thehazard switch 171 is detected again), the hazard light controller 161transitions from the fourth state S4 to the fifth state S5 (the arrowC45 in FIG. 2) and outputs a flashing control signal with the value “0”.In the fifth state S5, the lights 163L, 163R, 164L, and 164R are eachcontrolled to be turned off.

At time t7, when a hazard-switch pressing signal with the value “1” isinput from the hazard switch 171 (in other words, when depression of thehazard switch 171 is detected again), the hazard light controller 161transitions from the fifth state S5 to the sixth state S6 (the arrow C56in FIG. 2) and outputs a flashing control signal with the value “1”. Inthe sixth state S6, the lights 163L, 163R, 164L, and 164R are eachcontrolled to flash.

At time t8, when a hazard control request with the value “2” (forturn-off) is input in association with, for example, the completion ofthe automatic stop control by the automatic stop controller 122, thehazard light controller 161 transitions from the sixth state S6 to thesecond state S2 (the arrow C62 in FIG. 2) and outputs a flashing controlsignal with the value “1”. In the second state S2, the lights 163L,163R, 164L, and 164R are each controlled to flash. The hazard lightcontroller 161 further sets the manual flashing state variable to 1.

Next, relationships between inputs for the hazard light controller 161and a request output from the hazard light controller 161 at times t10to t16 will be described with reference to FIGS. 4A to 4C.

At time t10, the hazard light controller 161 is in the first state S1.In the first state S1, the hazard light controller 161 receives input ofa hazard control request with the value “0” and a hazard-switch pressingsignal with the value “0”, and the hazard light controller 161 outputs aflashing control signal with the value “0”. In the first state S1, thelights 163L, 163R, 164L, and 164R are each controlled to be turned off.The manual flashing state variable is set to 0.

At time t11, when a hazard-switch pressing signal with the value “1” isinput from the hazard switch 171 (in other words, when depression of thehazard switch 171 is detected), the hazard light controller 161transitions from the first state S1 to the second state S2 (the arrowC12 in FIG. 2) and outputs a flashing control signal with the value “1”.In the second state S2, the lights 163L, 163R, 164L, and 164R are eachcontrolled to flash. The hazard light controller 161 further sets themanual flashing state variable to 1.

At time t12, when a hazard control request with the value “1” (forflashing) is input in association with, for example, the start ofautomatic stop control by the automatic stop controller 122, the hazardlight controller 161 transitions from the second state S2 to the fourthstate S4 (the arrow C24 in FIG. 2) and outputs a flashing control signalwith the value “1”. In the fourth state S4, the lights 163L, 163R, 164L,and 164R are each controlled to flash.

At time t13, when a hazard control request with the value “3” (fortemporary stop of flashing) is input in association with, for example,the start of a lane change during execution of the automatic stopcontrol by the automatic stop controller 122, the hazard lightcontroller 161 transitions from the fourth state S4 to the third stateS3 (the arrow C43 in FIG. 2) and outputs a flashing control signal withthe value “0”. In the third state S3, the lights 163L, 163R, 164L, and164R are each controlled to be turned off.

At time t14, when a hazard control request with the value “1” (forflashing) is input in association with, for example, the completion ofthe lane change during execution of the automatic stop control by theautomatic stop controller 122, the hazard light controller 161transitions from the third state S3 to the fourth state S4 (the arrowC34 in FIG. 2) and outputs a flashing control signal with the value “1”.In the fourth state S4, the lights 163L, 163R, 164L, and 164R are eachcontrolled to flash.

At time t15, when a hazard-switch pressing signal with the value “1” isinput from the hazard switch 171 (in other words, when depression of thehazard switch 171 is detected again), the hazard light controller 161transitions from the fourth state S4 to the fifth state S5 (the arrowC45 in FIG. 2) and outputs a flashing control signal with the value “0”.In the fifth state S5, the lights 163L, 163R, 164L, and 164R are eachcontrolled to be turned off.

At time t16, when a hazard control request with the value “2” (forturn-off) is input in association with, for example, the completion ofthe automatic stop control by the automatic stop controller 122, thehazard light controller 161 transitions from the fifth state S5 to thefirst state S1 (the arrow C51 in FIG. 2) and outputs a flashing controlsignal with the value “0”. In the first state S1, the lights 163L, 163R,164L, and 164R are each controlled to be turned off. The hazard lightcontroller 161 further sets the manual flashing state variable to 0.

Relationships Between Activation of Emergency Stop System and States ofHazard Lights

Next, relationships between the activation of the emergency stop system1 and the states of the hazard lights will be described with referenceto FIGS. 5A to 12B.

Activation of Emergency Stop System in Automatic Stop Control

FIG. 5A and FIG. 5B are diagrams depicting the activation of theemergency stop system 1 in automatic stop control. In FIG. 5A and FIG.5B, at time T101, the hazard light controller 161 is in the first stateS1 and the manual flashing state variable is set to 0.

As illustrated in FIG. 5A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T101), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

In response to the input of the emergency-stop-switch pressing signal,the emergency warning system 112 places a call to an external emergencycall center.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T101 to time T103). Thecontinuous-driving-difficulty determination period is a period fordetermining whether or not it is difficult for the driver of the vehicleto continue to drive the vehicle. Even if it is difficult for the driverof the vehicle to continue to drive the vehicle, the passenger maycontinue the steering operation. In this embodiment, therefore, theautomatic stop controller 122, which monitors the presence or absence ofthe accelerator operation, may additionally or instead monitor an amountof steering operation, for example.

The “continuous-driving-difficulty determination period” corresponds toa “first period” disclosed herein.

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T103).The term “absence of the accelerator operation”, as used herein, is usedto include not only the state in which the accelerator opening degree iszero but also the state in which the accelerator opening degree is lessthan or equal to a predetermined value.

Note that if an emergency-stop-switch pressing signal is input after theabsence of the accelerator operation has been continuously detected forthe continuous-driving-difficulty determination period, the automaticstop controller 122 may start braking control and steering control,described below, at the time T103 without monitoring the presence orabsence of the accelerator operation. The automatic stop controller 122may start braking control and steering control on condition that eitherthe condition in which an emergency-stop-switch pressing signal is inputor the condition in which the absence of the accelerator operation iscontinuously detected for the continuous-driving-difficultydetermination period is met.

At the time T103, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T103, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T103, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. Each of the lights 163L, 163R, 164L, and 164R startsflashing accordingly.

When the automatic stop controller 122 determines that no lane change isnecessary (time T104), the automatic stop controller 122 continuouslyoutputs a request to the stability control unit 131 and the steeringcontrol unit 132 to cause the vehicle to come to a stop in the currentlane.

At time T105, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T106, when the stop control for the vehicle with the use of theelectric parking brake is completed (in other words, when the automaticstop controller 122 detects the completion of the stop control for thevehicle), the automatic stop controller 122 stops the output of anautomatic stop control request to terminate the automatic stop control,and outputs a hazard control request with the value “2” (for turn-off)to the hazard light controller 161. In accordance with the hazardcontrol request (for turn-off) and the manual flashing state variable,which is 0, the hazard light controller 161 transitions from the fourthstate S4 to the first state S1 (the arrow C41 in FIG. 2) and outputs aflashing control request with the value “0” to the lights 163L, 163R,164L, and 164R. Each of the lights 163L, 163R, 164L, and 164R is turnedoff accordingly.

Activation of Emergency Stop System in Response to Depression of HazardSwitch Before Execution of Automatic Stop Control

FIG. 6A and FIG. 6B are diagrams depicting the activation of theemergency stop system 1 in response to depression of the hazard switch171 before the execution of automatic stop control. In FIG. 6A and FIG.6B, at time T201, the hazard light controller 161 is in the first stateS1 and the manual flashing state variable is set to 0.

As illustrated in FIG. 6A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T201), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

In response to the input of the emergency-stop-switch pressing signal,the emergency warning system 112 places a call to an external emergencycall center.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T201 to time T203).

At time T202, when a hazard-switch pressing signal with the value “1” isoutput from the hazard switch 171 to the hazard light controller 161,the hazard light controller 161 transitions from the first state S1 tothe second state S2 (the arrow C12 in FIG. 2) and outputs a flashingcontrol request with the value “1” to the lights 163L, 163R, 164L, and164R. As illustrated in FIG. 6B, each of the lights 163L, 163R, 164L,and 164R starts flashing accordingly. The hazard light controller 161further sets the manual flashing state variable to 1.

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T203).

At the time T203, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the secondstate S2 to the fourth state S4 (the arrow C24 in FIG. 2) and each ofthe lights 163L, 163R, 164L, and 164R continues to flash.

When the automatic stop controller 122 determines that no lane change isnecessary (time T204), the automatic stop controller 122 continuouslyoutputs a request to the stability control unit 131 and the steeringcontrol unit 132 to cause the vehicle to come to a stop in the currentlane.

At time T205, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T206, when the stop control for the vehicle with the use of theelectric parking brake is completed, the automatic stop controller 122stops the output of an automatic stop control request to terminate theautomatic stop control, and outputs a hazard control request with thevalue “2” (for turn-off) to the hazard light controller 161. Inaccordance with the hazard control request (for turn-off) and the manualflashing state variable, which is 1, the hazard light controller 161transitions from the fourth state S4 to the second state S2 (the arrowC42 in FIG. 2) and each of the lights 163L, 163R, 164L, and 164Rcontinues to flash.

At time T207, when a hazard-switch pressing signal with the value “1” isoutput from the hazard switch 171 to the hazard light controller 161,the hazard light controller 161 transitions from the second state S2 tothe first state S1 (the arrow C21 in FIG. 2) and outputs a flashingcontrol request with the value “0” to the lights 163L, 163R, 164L, and164R. Each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly. The hazard light controller 161 further sets the manualflashing state variable to 0.

Activation of Emergency Stop System when Automatic Stop Control InvolvesLane Change

FIG. 7A and FIG. 7B are diagrams depicting the activation of theemergency stop system 1 when the automatic stop control involves a lanechange. In FIG. 7A and FIG. 7B, at time T111, the hazard lightcontroller 161 is in the first state S1 and the manual flashing statevariable is set to 0.

As illustrated in FIG. 7A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T111), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

In response to the input of the emergency-stop-switch pressing signal,the emergency warning system 112 places a call to an external emergencycall center.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T111 to time T113).

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T113).

At the time T113, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T113, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T113, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. Each of the lights 163L, 163R, 164L, and 164R startsflashing accordingly.

When the automatic stop controller 122 determines that a lane change isnecessary (time T114), the automatic stop controller 122 outputs arequest to the stability control unit 131 to keep the speed of thevehicle, and outputs a lane change request to the steering control unit132. The automatic stop controller 122 further outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. The hazard light controller 161 accordinglytransitions from the fourth state S4 to the third state S3 (the arrowC43 in FIG. 2) and outputs a flashing control signal with the value “0”to the lights 163L, 163R, 164L, and 164R.

Consequently, as illustrated in FIG. 7B, each of the lights 163L, 163R,164L, and 164R temporarily stops flashing. However, some lights (in FIG.7B, the left front light 163L and the left rear light 164L) startflashing as turn signal lights (direction indicators).

At time T115, when the lane change is completed, the automatic stopcontroller 122 outputs a deceleration request and a deceleration to thestability control unit 131. The automatic stop controller 122 furtheroutputs a lane-keeping request and a steering request value to thesteering control unit 132.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “1” (for flashing) to the hazard light controller161. The hazard light controller 161 accordingly transitions from thethird state S3 to the fourth state S4 (the arrow C34 in FIG. 2) andoutputs a flashing control signal with the value “1” to the lights 163L,163R, 164L, and 164R.

Consequently, as illustrated in FIG. 7B, each of the lights 163L, 163R,164L, and 164R resumes flashing.

At time T116, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T117, when the stop control for the vehicle with the use of theelectric parking brake is completed, the automatic stop controller 122stops the output of an automatic stop control request to terminate theautomatic stop control, and outputs a hazard control request with thevalue “2” (for turn-off) to the hazard light controller 161. Inaccordance with the hazard control request (for turn-off) and the manualflashing state variable, which is 0, the hazard light controller 161transitions from the fourth state S4 to the first state S1 (the arrowC41 in FIG. 2) and outputs a flashing control request with the value “0”to the lights 163L, 163R, 164L, and 164R. Each of the lights 163L, 163R,164L, and 164R is then turned off.

Activation of Emergency Stop System in Response to Depression of HazardSwitch Before Execution of Automatic Stop Control when Automatic StopControl Involves Lane Change

FIG. 8A and FIG. 8B are diagrams depicting the activation of theemergency stop system 1 in response to depression of the hazard switch171 before the execution of automatic stop control when the automaticstop control involves a lane change. In FIG. 8A and FIG. 8B, at timeT211, the hazard light controller 161 is in the first state S1 and themanual flashing state variable is set to 0.

As illustrated in FIG. 8A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T211), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

In response to the input of the emergency-stop-switch pressing signal,the emergency warning system 112 places a call to an external emergencycall center.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T211 to time T213).

At time T212, when a hazard-switch pressing signal with the value “1” isoutput from the hazard switch 171 to the hazard light controller 161,the hazard light controller 161 transitions from the first state S1 tothe second state S2 (the arrow C12 in FIG. 2) and outputs a flashingcontrol request with the value “1” to the lights 163L, 163R, 164L, and164R. As illustrated in FIG. 8B, each of the lights 163L, 163R, 164L,and 164R starts flashing accordingly. The hazard light controller 161further sets the manual flashing state variable to 1.

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T213).

At the time T213, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T213, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T213, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the secondstate S2 to the fourth state S4 (the arrow C24 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. Each of the lights 163L, 163R, 164L, and 164R continuesto flash accordingly.

When the automatic stop controller 122 determines that a lane change isnecessary (time T214), the automatic stop controller 122 outputs arequest to the stability control unit 131 to keep the speed of thevehicle, and outputs a lane change request to the steering control unit132. The automatic stop controller 122 further outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. The hazard light controller 161 accordinglytransitions from the fourth state S4 to the third state S3 (the arrowC43 in FIG. 2) and outputs a flashing control signal with the value “0”to the lights 163L, 163R, 164L, and 164R.

Consequently, as illustrated in FIG. 8B, each of the lights 163L, 163R,164L, and 164R temporarily stops flashing. However, some lights (in FIG.8B, the left front light 163L and the left rear light 164L) startflashing as turn signal lights (direction indicators).

At time T215, when the lane change is completed, the automatic stopcontroller 122 outputs a deceleration request and a deceleration to thestability control unit 131. The automatic stop controller 122 furtheroutputs a lane-keeping request and a steering request value to thesteering control unit 132.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “1” (for flashing) to the hazard light controller161. The hazard light controller 161 accordingly transitions from thethird state S3 to the fourth state S4 (the arrow C34 in FIG. 2) andoutputs a flashing control signal with the value “1” to the lights 163L,163R, 164L, and 164R.

Consequently, as illustrated in FIG. 8B, each of the lights 163L, 163R,164L, and 164R resumes flashing.

At time T216, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T217, when the stop control for the vehicle with the use of theelectric parking brake is completed, the automatic stop controller 122stops the output of an automatic stop control request to terminate theautomatic stop control, and outputs a hazard control request with thevalue “2” (for turn-off) to the hazard light controller 161. Inaccordance with the hazard control request (for turn-off) and the manualflashing state variable, which is 1, the hazard light controller 161transitions from the fourth state S4 to the second state S2 (the arrowC42 in FIG. 2) and outputs a flashing control request with the value “1”to the lights 163L, 163R, 164L, and 164R. Each of the lights 163L, 163R,164L, and 164R then continues to flash.

At time T218, when a hazard-switch pressing signal with the value “1” isoutput from the hazard switch 171 to the hazard light controller 161,the hazard light controller 161 transitions from the second state S2 tothe first state S1 (the arrow C21 in FIG. 2) and outputs a flashingcontrol request with the value “0” to the lights 163L, 163R, 164L, and164R. Each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly. The hazard light controller 161 further sets the manualflashing state variable to 0.

Activation of Emergency Stop System Upon Detection of ContinuousAccelerator Operation During Execution of Automatic Stop Control

FIG. 9A and FIG. 9B are diagrams depicting the activation of theemergency stop system 1 upon detection of an accelerator operationduring execution of automatic stop control. In FIG. 9A and FIG. 9B, attime T121, the hazard light controller 161 is in the first state S1 andthe manual flashing state variable is set to 0.

As illustrated in FIG. 9A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T121), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T121 to time T122).

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T122).

At the time T122, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T122, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T122, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. As illustrated in FIG. 9B, each of the lights 163L,163R, 164L, and 164R starts flashing accordingly.

When the operation detector 123 detects an accelerator operation (timeT124), the automatic stop controller 122 outputs a request to thestability control unit 131 to interrupt the deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. In accordance with the hazard controlrequest (for temporary stop of flashing), the hazard light controller161 transitions from the fourth state S4 to the third state S3 (thearrow C43 in FIG. 2) and outputs a flashing control request with thevalue “0” to the lights 163L, 163R, 164L, and 164R. As illustrated inFIG. 9B, each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly.

At time T125, if the accelerator operation has been continuouslydetected by the operation detector 123 for a predetermined drivingintention confirmation period (for example, four seconds), the automaticstop controller 122 makes a request to the steering control unit 132 tocancel the lane-keeping control. The driving intention confirmationperiod is a period for confirming the intention to drive the vehicle.The driving intention confirmation period corresponds to a “secondperiod”, a “third period”, and a “fourth period” disclosed herein.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “2” (for turn-off) to the hazard light controller161. In accordance with the hazard control request (for turn-off) andthe manual flashing state variable, which is 0, the hazard lightcontroller 161 transitions from the third state S3 to the first state S1(the arrow C31 in FIG. 2) and outputs a flashing control request withthe value “0” to the lights 163L, 163R, 164L, and 164R. As illustratedin FIG. 9B, each of the lights 163L, 163R, 164L, and 164R continues tobe turned off accordingly.

Activation of Emergency Stop System Upon Detection of Operation ofHazard Switch and Detection of Continuous Accelerator Operation DuringExecution of Automatic Stop Control

FIG. 10A and FIG. 10B are diagrams depicting the activation of theemergency stop system 1 upon detection of an operation of the hazardswitch 171 and detection of a continuous accelerator operation duringexecution of automatic stop control. In FIG. 10A and FIG. 10B, at timeT221, the hazard light controller 161 is in the first state S1 and themanual flashing state variable is set to 0.

As illustrated in FIG. 10A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T221), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T221 to time T222).

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T222).

At the time T222, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T222, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T222, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. As illustrated in FIG. 10B, each of the lights 163L,163R, 164L, and 164R starts flashing accordingly.

At time T223, for example, when depression of the hazard switch 171 bythe vehicle driver who wishes to resume driving the vehicle is detected,the hazard switch 171 outputs a hazard-switch pressing signal with thevalue “1” to the hazard light controller 161. In accordance with thehazard-switch pressing signal, the hazard light controller 161transitions from the fourth state S4 to the fifth state S5 (the arrowC45 in FIG. 2) and outputs a flashing control request with the value “0”to the lights 163L, 163R, 164L, and 164R. As illustrated in FIG. 10B,each of the lights 163L, 163R, 164L, and 164R is turned off accordingly.

When the operation detector 123 detects an accelerator operation (timeT224), the automatic stop controller 122 outputs a request to thestability control unit 131 to interrupt the deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. Even when the hazard control request (fortemporary stop of flashing) is input, the hazard light controller 161 isstill in the fifth state S5 and continuously outputs a flashing controlrequest with the value “0” to the lights 163L, 163R, 164L, and 164R. Asillustrated in FIG. 10B, each of the lights 163L, 163R, 164L, and 164Rcontinues to be turned off accordingly.

At time T225, if the accelerator operation has been continuouslydetected by the operation detector 123 for a predetermined drivingintention confirmation period (for example, four seconds), the automaticstop controller 122 makes a request to the steering control unit 132 tocancel the lane-keeping control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “2” (for turn-off) to the hazard light controller161. In accordance with the hazard control request (for turn-off), thehazard light controller 161 transitions from the fifth state S5 to thefirst state S1 (the arrow C51 in FIG. 2) and outputs a flashing controlrequest with the value “0” to the lights 163L, 163R, 164L, and 164R. Asillustrated in FIG. 10B, each of the lights 163L, 163R, 164L, and 164Rcontinues to be turned off accordingly.

Activation of Emergency Stop System Upon Detection of TemporaryAccelerator Operation During Execution of Automatic Stop Control

FIG. 11A and FIG. 11B are diagrams depicting the activation of theemergency stop system 1 upon detection of a temporary acceleratoroperation during execution of automatic stop control. In FIG. 11A andFIG. 11B, at time T131, the hazard light controller 161 is in the firststate S1 and the manual flashing state variable is set to 0.

As illustrated in FIG. 11A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T131), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T131 to time T132).

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T132).

At the time T132, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T132, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T132, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. As illustrated in FIG. 11B, each of the lights 163L,163R, 164L, and 164R starts flashing accordingly.

When the operation detector 123 detects an accelerator operation (timeT133), the automatic stop controller 122 outputs a request to thestability control unit 131 to interrupt the deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. In accordance with the hazard controlrequest (for temporary stop of flashing), the hazard light controller161 transitions from the fourth state S4 to the third state S3 (thearrow C43 in FIG. 2) and outputs a flashing control request with thevalue “0” to the lights 163L, 163R, 164L, and 164R. As illustrated inFIG. 11B, each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly.

At time T135, if the operation detector 123 has detected the acceleratoroperation for a period less than a predetermined driving intentionconfirmation period, the automatic stop controller 122 makes a requestto the stability control unit 131 to resume deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “1” (for flashing) to the hazard light controller161. In accordance with the hazard control request (for flashing), thehazard light controller 161 transitions from the third state S3 to thefourth state S4 (the arrow C34 in FIG. 2) and outputs a flashing controlrequest with the value “1” to the lights 163L, 163R, 164L, and 164R. Asillustrated in FIG. 11B, each of the lights 163L, 163R, 164L, and 164Rresumes flashing accordingly.

At time T136, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T137, when the stop control for the vehicle with the use of theelectric parking brake is completed, the automatic stop controller 122stops the output of an automatic stop control request to terminate theautomatic stop control, and outputs a hazard control request with thevalue “2” (for turn-off) to the hazard light controller 161. Inaccordance with the hazard control request (for turn-off) and the manualflashing state variable, which is 0, the hazard light controller 161transitions from the fourth state S4 to the first state S1 (the arrowC41 in FIG. 2) and outputs a flashing control request with the value “0”to the lights 163L, 163R, 164L, and 164R. As illustrated in FIG. 11B,each of the lights 163L, 163R, 164L, and 164R is then turned off.

Activation of Emergency Stop System Upon Detection of TemporaryAccelerator Operation and Detection of Depression of Hazard SwitchDuring Execution of Automatic Stop Control

FIG. 12A and FIG. 12B are diagrams depicting the activation of theemergency stop system 1 upon detection of a temporary acceleratoroperation and detection of depression of the hazard switch 171 duringexecution of automatic stop control. In FIG. 12A and FIG. 12B, at timeT231, the hazard light controller 161 is in the first state S1 and themanual flashing state variable is set to 0.

As illustrated in FIG. 12A, when depression of the emergency stop switch111 by a vehicle occupant (the driver or a passenger) is detected (seethe time T231), the emergency stop switch 111 outputs anemergency-stop-switch pressing signal to the emergency warning system112 (see FIG. 1) and the automatic stop controller 122.

Further, the automatic stop controller 122 refers to the acceleratoropening degree information input from the operation detector 123 for apredetermined continuous-driving-difficulty determination period (forexample, three seconds) to monitor the presence or absence of theaccelerator operation (the time T231 to time T232).

If the absence of the accelerator operation has been continuouslydetected for the continuous-driving-difficulty determination period, theautomatic stop controller 122 outputs a braking control request, adeceleration, a steering request, a steering request value, a hazardcontrol request, and so on to start automatic stop control and also tostart monitoring the presence or absence of an override operation by thedriver and determining the necessity of a lane change (the time T232).

At the time T232, the stability control unit 131 starts the execution ofbraking control at the designated deceleration (“deceleration control”)in accordance with the braking control request and the decelerationinput from the automatic stop controller 122, and outputs a turn-onsignal to the stop light 133 (see FIG. 1).

At the time T232, the steering control unit 132 performs lane-keepingcontrol to prevent the vehicle from exiting the current lane inaccordance with the steering request and the steering request valueinput from the automatic stop controller 122.

At the time T232, the automatic stop controller 122 outputs a hazardcontrol request with the value “1” (for flashing) to the hazard lightcontroller 161. In accordance with the hazard control request (forflashing), the hazard light controller 161 transitions from the firststate S1 to the fourth state S4 (the arrow C14 in FIG. 2) and outputs aflashing control request with the value “1” to the lights 163L, 163R,164L, and 164R. As illustrated in FIG. 12B, each of the lights 163L,163R, 164L, and 164R starts flashing accordingly.

When the operation detector 123 detects an accelerator operation (timeT233), the automatic stop controller 122 outputs a request to thestability control unit 131 to interrupt the deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “3” (for temporary stop of flashing) to thehazard light controller 161. In accordance with the hazard controlrequest (for temporary stop of flashing), the hazard light controller161 transitions from the fourth state S4 to the third state S3 (thearrow C43 in FIG. 2) and outputs a flashing control request with thevalue “0” to the lights 163L, 163R, 164L, and 164R. As illustrated inFIG. 12B, each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly.

At time T234, for example, when depression of the hazard switch 171 bythe vehicle driver who wishes to interrupt the accelerator operation isdetected, the hazard switch 171 outputs a hazard-switch pressing signalwith the value “1” to the hazard light controller 161. In accordancewith the hazard-switch pressing signal, the hazard light controller 161transitions from the third state S3 to the sixth state S6 (the arrow C36in FIG. 2) and outputs a flashing control request with the value “1” tothe lights 163L, 163R, 164L, and 164R. As illustrated in FIG. 12B, eachof the lights 163L, 163R, 164L, and 164R resumes flashing accordingly.

At time T235, if the operation detector 123 has detected the acceleratoroperation for a period less than a predetermined driving intentionconfirmation period, the automatic stop controller 122 makes a requestto the stability control unit 131 to resume deceleration control.

Further, the automatic stop controller 122 outputs a hazard controlrequest with the value “1” (for flashing) to the hazard light controller161. In accordance with the hazard control request (for flashing), thehazard light controller 161 does not transition from the sixth state S6and continuously outputs a flashing control request with the value “1”to the lights 163L, 163R, 164L, and 164R. As illustrated in FIG. 12B,each of the lights 163L, 163R, 164L, and 164R continues to flashaccordingly.

At time T236, when the vehicle is able to come to a stop, each of thestability control unit 131 and the steering control unit 132 performscontrol to bring the vehicle to a stop with the use of an electricparking brake and to hold the vehicle in the parked state.

At time T237, when the stop control for the vehicle with the use of theelectric parking brake is completed, the automatic stop controller 122stops the output of an automatic stop control request to terminate theautomatic stop control, and outputs a hazard control request with thevalue “2” (for turn-off) to the hazard light controller 161. Inaccordance with the hazard control request (for turn-off), the hazardlight controller 161 transitions from the sixth state S6 to the secondstate S2 (the arrow C62 in FIG. 2) and outputs a flashing controlrequest with the value “1” to the lights 163L, 163R, 164L, and 164R.Each of the lights 163L, 163R, 164L, and 164R then continues to flash.

At time T238, when a hazard-switch pressing signal with the value “1” isoutput from the hazard switch 171 to the hazard light controller 161,the hazard light controller 161 transitions from the second state S2 tothe first state S1 (the arrow C21 in FIG. 2) and outputs a flashingcontrol request with the value “0” to the lights 163L, 163R, 164L, and164R. Each of the lights 163L, 163R, 164L, and 164R is turned offaccordingly. The hazard light controller 161 further sets the manualflashing state variable to 0.

Operation and Advantages of this Embodiment

In the emergency stop system 1, while automatic stop control is notbeing performed, the hazard light controller 161 allows each of thelights 163L, 163R, 164L, and 164R to be switched between a flashingstate (the second state S2) and a turned-off state (the first state S1)each time the hazard switch 171 is pressed. Since the hazard switch 171is implemented as a momentary switch, the hazard switch 171 is kept in afree state regardless of whether the hazard lights are in the flashingstate (the second state S2) or in the turned-off state (the first stateS1).

In addition, when the hazard lights are controlled to be in the flashingstate by the hazard light controller 161 (see C14 and C24 in FIG. 2) inresponse to the execution of automatic stop control by the automaticstop controller 122, similarly to when each of the lights 163L, 163R,164L, and 164R is in the flashing state while automatic stop control isnot being performed, the hazard switch 171 is in a free state. Thisresults in elimination or reduction of the awkward feeling that the userexperiences because the state of the hazard switch 171 and the flashingstate of the lights 163L, 163R, 164L, and 164R are contrary to what isexpected by the user.

In addition, the hazard light controller 161 allows each of the lights163L, 163R, 164L, and 164R to be turned off by a one-time depression ofthe hazard switch 171 (see C45 in FIG. 2). Also in this case, similarlyto when each of the lights 163L, 163R, 164L, and 164R is in theturned-off state while automatic stop control is not being performed,the hazard switch 171 is in a free state. This allows elimination orreduction of the awkward feeling that the user experiences for the stateof the hazard switch and allows elimination or reduction ofinconvenience that the user incurs for the hazard switch when turningoff the hazard lights.

As described above, the emergency stop system 1 allows elimination orreduction of the user's awkward feeling and inconvenience even when theuser performs an operation during the flashing of each of the lights163L, 163R, 164L, and 164R which is involved in a process for bringingthe vehicle to an automatic stop.

In the emergency stop system 1, furthermore, the automatic stopcontroller 122 performs automatic stop control on condition that theemergency stop switch 111 has been operated (T103 in FIG. 5A, T203 inFIG. 6A, T113 in FIG. 7A, T213 in FIG. 8A, T122 in FIG. 9A, T222 in FIG.10A, T132 in FIG. 11A, T232 in FIG. 12A). This allows the intention ofthe user to be reflected when automatic stop control is performed.

In some cases, such as when the emergency stop switch 111 has beenpressed unintentionally due to an operation error or the like but theuser does not recognize the depression of the emergency stop switch 111or when the user wishes to temporarily continue to drive the vehiclealthough the user has intentionally pressed the emergency stop switch111, the user may wish to turn off the hazard lights (for example, thetime T223 in FIG. 10A). In such cases, the user may attempt to turn offthe hazard lights by using the hazard switch 171. As described above,the hazard lights are turned off with a single operation of the hazardswitch (the time T223 in FIG. 10A).

In the emergency stop system 1, furthermore, the automatic stopcontroller 122 performs automatic stop control on condition that theabsence of the predetermined driving operation is continuously detectedby the operation detector 123 for a predeterminedcontinuous-driving-difficulty determination period.

However, even during execution of the automatic stop control, the user(the vehicle driver) may wish to turn off the hazard lights by using thehazard switch 171 in some cases such as when the user wishes to resumethe driving operation. Also in such cases, in the emergency stop system1, a one-time depression of hazard switch allows the hazard lightcontroller 161 to turn off the hazard lights (the time T223 in FIG.10A).

In the emergency stop system 1, furthermore, if the presence of thepredetermined driving operation is continuously detected by theoperation detector 123 for a predetermined driving intentionconfirmation period during execution of the automatic stop control (T225in FIG. 10A), the automatic stop control is terminated. If the drivingoperation detected by the operation detector 123 continues for apredetermined driving intention confirmation period during execution ofthe automatic stop control, the vehicle driver is more likely to have adriving intention. Thus, by terminating the automatic stop control, itmay be possible to achieve the control intended by the vehicle driver.

In some cases, furthermore, the user attempts to turn off the hazardlights by using the hazard switch 171 before or after the resumption ofdriving of the vehicle (T223 in FIG. 10A). In such cases, the hazardlight controller 161 causes the hazard lights to be turned off inresponse to a one-time depression of the hazard switch 171 (T223 in FIG.10A). This allows elimination or reduction of the awkward feeling thatthe user experiences.

While the hazard lights are flashing in accordance with automatic stopcontrol, if the automatic stop control is completed, in many case, it ispredicted that the flashing of the hazard lights will no longer benecessary. Thus, even if the hazard light controller 161 terminates theflashing of the hazard lights in response to the completion of theautomatic stop control (the time T106 in FIG. 5A, the time T117 in FIG.7A, and the time T137 in FIG. 11A), the user will not feel very awkward.

In contrast, if the user presses the hazard switch 171 to bring thehazard lights into the flashing state, it is predicted that the userwill wish to flash the hazard lights regardless of the execution ofautomatic stop control. The hazard light controller 161 causes thehazard lights to continue to flash even after the automatic stop controlhas been completed (the time T206 in FIG. 6A, the time T217 in FIG. 8A,the time T237 in FIG. 12A), thus reducing or preventing the awkwardfeeling that the user experiences.

In addition, when a lane change is performed, it is predicted that theuser will expect that the flashing of the hazard lights will be stopped.To address this situation, in the emergency stop system 1 according tothis embodiment, the hazard light controller 161 turns off the hazardlights if a lane change is performed during execution of the automaticstop control (the time T114 in FIG. 7A and the time T214 in FIG. 8A).

In contrast, when the lane change is completed, it is predicted that theuser will expect that the flashing of the hazard lights will be resumed.To address this situation, in the emergency stop system 1 having theconfiguration described above, the hazard light controller 161 causesthe hazard lights to flash after the lane change has been completed (thetime T115 in FIG. 7A and the time T215 in FIG. 8A).

Consequently, the hazard lights operate, as expected by the user, when alane change is performed. This may eliminate or reduce the awkwardfeeling that the user experiences.

In the emergency stop system 1, in response to an accelerator operationbeing detected by the operation detector 123 during execution of theautomatic stop control, the automatic stop controller 122 interrupts theautomatic stop control and the hazard light controller 161 turns off thehazard lights (the time T124 in FIG. 9A, the time T224 in FIG. 10A, thetime T133 in FIG. 11A, and the time T233 in FIG. 12A). This allows theuser and occupants of other vehicles to recognize interruption of theautomatic stop control.

In addition, if the accelerator operation continues for a drivingintention confirmation period or longer, it is predicted that theaccelerator operation is an operation based on the driving intention ofthe vehicle driver, whereas, if the duration of the acceleratoroperation is less than the driving intention confirmation period, it isdifficult to determine whether or not the acceleration operation isbased on the driving intention of the driver. To address this situation,the automatic stop controller 122 performs control to terminate theautomatic stop control or to resume the automatic stop control inaccordance with whether or not the acceleration operation continues forthe driving intention confirmation period or longer (the time T125 inFIG. 9A, the time T225 in FIG. 10A, the time T135 in FIG. 11A, and thetime T235 in FIG. 12A). Thus, the control intended by the vehicle driveris achievable.

Furthermore, the hazard light controller 161 causes the hazard lights toresume flashing in response to the resumption of the automatic stopcontrol (the time T135 in FIG. 11A). This allows the user and occupantsof other nearby vehicles to recognize the resumption of the automaticstop control.

As described above, the emergency stop system having the configurationdescribed above allows the driving intention of the user to be reflectedand allows the hazard lights to be controlled to flash or stop flashingin accordance with the state of the execution of automatic stop control.This allows the user and occupants of other vehicles to recognize thestate of the execution of automatic stop control.

In the emergency stop system 1 having the configuration described above,when the hazard switch 171 is pressed even though the hazard lights havebeen turned off in association with automatic stop control (the timeT234 in FIG. 12A), it is predicted that the user will have an intentionto resume flashing the hazard lights. To address this situation, thehazard light controller 161 resumes flashing the hazard lights. Thus,the hazard lights are controlled to flash in accordance with the user'sintention.

Modifications

In the foregoing embodiment, the automatic stop controller 122 causesthe hazard lights to be automatically turned off (outputs a hazardcontrol request (for turn-off) to the hazard light controller 161) inresponse to the completion of the automatic stop control when theparking of the vehicle has been completed (T106 in FIG. 5A, T206 in FIG.6A, T117 in FIG. 7A, T217 in FIG. 8A, T137 in FIG. 11A, and T237 in FIG.12A). Alternatively, the automatic stop controller 122 may cause thehazard lights to continue to flash, without automatically turning offthe hazard lights, after the completion of the automatic stop controlwhen the parking of the vehicle has been completed. In this case, thehazard light controller 161 continues flashing of the hazard lightsuntil the hazard switch 171 is pressed.

In the foregoing embodiment, the automatic stop controller 122 startsdetermination as to whether or not it is difficult to continue to drivethe vehicle after the detection of depression of the emergency stopswitch 111 (T101 in FIG. 5A, T201 in FIG. 6A, T111 in FIG. 7A, T211 inFIG. 8A, T121 in FIG. 9A, T221 in FIG. 10A, T131 in FIG. 11A, and T231in FIG. 12A), and, after it has been determined that it is difficult tocontinue to drive the vehicle, the automatic stop controller 122 startsdeceleration control and causes the hazard lights to automatically flash(outputs a hazard control request (for flashing) to the hazard lightcontroller 161) (T103 in FIG. 5A, T203 in FIG. 6A, T113 in FIG. 7A, T213in FIG. 8A, T122 in FIG. 9A, T222 in FIG. 10A, T132 in FIG. 11A, andT232 in FIG. 12A).

Alternatively, the automatic stop controller 122 may start determinationas to whether or not it is difficult to continue to drive the vehicleand start deceleration control with comparatively weak deceleration(deceleration at a comparatively low deceleration) after detection ofdepression of the emergency stop switch 111. In addition, after it hasbeen determined that it is difficult to continue to drive the vehicle,the automatic stop controller 122 may start deceleration control withcomparatively strong deceleration (deceleration at a comparatively highdeceleration). In this case, the automatic stop controller 122 may causethe hazard lights to automatically flash (output a hazard controlrequest (for flashing) to the hazard light controller 161) together withthe start of comparatively weak deceleration. Alternatively, theautomatic stop controller 122 may not cause the hazard lights to flash(may continue outputting a hazard control request (for keeping) to thehazard light controller 161) during the comparatively weak deceleration,and may cause the hazard lights to automatically flash (output a hazardcontrol request (for flashing) to the hazard light controller 161) afterthe transition to comparatively strong deceleration.

In the foregoing embodiment, the automatic stop controller 122 startsautomatic stop control by requiring the detection of depression of theemergency stop switch 111. Alternatively, even if depression of theemergency stop switch 111 has not been detected, the automatic stopcontroller 122 may start automatic stop control when the absence of thedriving operation is continuously detected for a predetermined period.Although a specific form of embodiment has been described above andillustrated in the accompanying drawings in order to be more clearlyunderstood, the above description is made by way of example and not aslimiting the scope of the invention defined by the accompanying claims.The scope of the invention is to be determined by the accompanyingclaims. Various modifications apparent to one of ordinary skill in theart could be made without departing from the scope of the invention. Theaccompanying claims cover such modifications.

We claim:
 1. An emergency stop system comprising: a hazard switch thatis a momentary switch configured to provide an instruction to flash orturn off hazard lights of a vehicle; an automatic stop controller thatperforms automatic stop control for causing the vehicle to automaticallystop when a predetermined condition is met; and a hazard lightcontroller that controls the hazard lights to: switch the hazard lightsbetween a flashing state and a turned-off state each time the hazardswitch is pressed by a user while the automatic stop control is notbeing performed, to bring the hazard lights into the flashing state uponstart of the automatic stop control, and to turn off the hazard lightsupon depression of the hazard switch while the hazard lights areflashing during execution of the automatic stop control, wherein thehazard light controller turns off the hazard lights upon depression ofthe hazard switch while the hazard lights are flashing even if theautomatic stop control is being performed.
 2. The emergency stop systemaccording to claim 1, further comprising an emergency stop switchprovided separately from the hazard switch, wherein the predeterminedcondition includes a condition in which the emergency stop switch ispressed.
 3. The emergency stop system according to claim 1, furthercomprising a driving operation detector that detects a presence orabsence of a predetermined driving operation of the vehicle, wherein thepredetermined condition includes a condition in which the absence of thepredetermined driving operation is continuously detected by the drivingoperation detector for a predetermined first period.
 4. The emergencystop system according to claim 1, further comprising a driving operationdetector that detects a presence or absence of a predetermined drivingoperation of the vehicle, wherein the automatic stop controllerterminates the automatic stop control in a case where the presence ofthe predetermined driving operation is continuously detected by thedriving operation detector for a predetermined second period duringexecution of the automatic stop control.
 5. The emergency stop systemaccording to claim 1, wherein the hazard light controller causes thehazard lights to be turned off upon completion of the automatic stopcontrol in a case where the hazard lights are brought into the flashingstate in accordance with the automatic stop control, and continues theflashing state of the hazard lights after completion of the automaticstop control in a case where the hazard lights are brought into theflashing state in response to depression of the hazard switch beforestart of the automatic stop control or during execution of the automaticstop control.
 6. The emergency stop system according to claim 1, whereinthe hazard light controller is configured to turn off the hazard lightswhen the automatic stop controller starts execution of predeterminedcontrol during execution of the automatic stop control, and to cause thehazard lights to resume flashing upon completion of the predeterminedcontrol during execution of the automatic stop control.
 7. The emergencystop system according to claim 6, wherein the predetermined controlcomprises a lane change that involves causing turn signal lights of thevehicle to flash.
 8. The emergency stop system according to claim 1,further comprising an acceleration operation detector that detects anacceleration operation of the vehicle, wherein the automatic stopcontroller is configured to interrupt the automatic stop control in acase where the acceleration operation is detected by the accelerationoperation detector during execution of the automatic stop control,wherein the automatic stop controller is configured to terminate theautomatic stop control in a case where the acceleration operation iscontinuously detected by the acceleration operation detector for apredetermined third period or longer after interruption of the automaticstop control, and resume the automatic stop control in a case where theacceleration operation is no longer detected by the accelerationoperation detector before the third period elapses after interruption ofthe automatic stop control, and wherein the hazard light controller isconfigured to turn off the hazard lights during interruption of theautomatic stop control, and to cause the hazard lights to resumeflashing in response to resumption of the automatic stop control.
 9. Theemergency stop system according to claim 8, wherein the hazard lightcontroller brings the hazard lights into the flashing state upondepression of the hazard switch while the hazard lights are turned offby interruption of the automatic stop control.
 10. The emergency stopsystem according to claim 1, wherein the hazard light controller storesa status indicator indicating a flashing instruction of the hazardlights and a turn-off instruction of the hazard lights, and the hazardlight controller switches the status indicator between the flashinginstruction and the turn-off instruction each time the hazard switch ispressed.
 11. The emergency stop system according to claim 10, whereinthe automatic stop controller sends to the hazard light controller aninstruction signal indicating a status of the hazard lights, and thehazard light controller controls the hazard lights by using combinationof the instruction signal and the status indicator.
 12. The emergencystop system according to claim 11, wherein the instruction signalincludes a flashing request, a temporary stop of flashing request, aturn-off of flashing request.
 13. The emergency stop system according toclaim 12, wherein the instruction signal further includes a keeping anexisting state of flashing or turn-off request.
 14. The emergency stopsystem according to claim 1, wherein the momentary switch is configuredto, when the momentary switch is pressed while in a free state withbeing in a released position, temporarily transition to an operatingstate with being in a depressed position and then return to the freestate such that the hazard switch is held in the free state when thehazard switch is not being operated by the user, regardless of whetherthe hazard lights are in a flashing state or a turned-off state.
 15. Anemergency stop method performed by a system including a hazard switchand an automatic stop controller, the hazard switch being a momentaryswitch configured to provide an instruction to flash or turn off hazardlights of a vehicle, the automatic stop controller performing automaticstop control for causing the vehicle to automatically stop when apredetermined condition is met, the emergency stop method comprising thesteps of: (i) switching the hazard lights between a flashing state and aturned-off state each time the hazard switch is pressed by a user whilethe automatic stop control is not being performed; (ii) bringing thehazard lights into the flashing state upon start of the automatic stopcontrol; and (iii) turning off the hazard lights upon depression of thehazard switch while the hazard lights are flashing during execution ofthe automatic stop control, wherein the step (iii) turns off the hazardlights upon depression of the hazard switch while the hazard lights areflashing even if the automatic stop control is being performed.